1. Technical Field
This device relates to negative air enclosures required for a work space during the removal of hazardous materials that create airborne particles within the work space.
2. Description of Prior Art
Prior Art systems and enclosures of this type have relied on decontamination chambers and work spaces that become sealed under loss of negative air pressure within the work space to trap and hold contaminated air within. A number of isolation devices have been used to prevent outward airflow of the decontaminated air under such loss, see for example U.S. Pat. Nos. 4,604,111, 4,801,312, 4,922,806, and 4,312,645 and U.S. Statutory Registration H460 and Statutory Registration H785.
In U.S. Pat. No. 4,604,111 an enclosure and a temporary wall in which doorways are formed and airflow is controlled by "flap seals" formed of plastic film sheets is shown that will close upon loss of negative air pressure within the work area sealing the same preventing contamination of the outside environment.
U.S. Pat. No. 4,801,312 an airflow hazardous material abatement method and system is disclosed wherein a decontamination enclosure is used having multiple chambers defined by flap sealed door-ways made of sheets of plastic film.
U.S. Pat. No. 4,922,806 refers to a door for negative air pressure enclosure in which access doors used in multiple chambers have flap seals for one-way inflow air movement with controlled door position from fully closed to partially open.
U.S. Pat. No. 4,312,645 a separation assembly having a filter mounted in an air duct so at least a section of the filter element can be moved from a filtering position to a bypass position as disclosed.
In U.S. Statutory Registration H460 a work place and decontamination room having doorways with multiple hinged doors all but one of which is provided with fixed louvers as disclosed.
Finally, in U.S. Statutory Registration H785 a decontamination apparatus and method is disclosed using a decontamination enclosure with multiple doors. Multiple filters are used between chambers to filter all inflow air only to the work space.